Geometrical factors in surface EMG of the vastus medialis and lateralis muscles

摘要: Abstract Surface EMG signals detected in dynamic conditions are affected by a number of artefacts. Among them geometrical factors play an important role. During movement the muscle slides with respect to skin because variation its length. Such shift can considerably modify sEMG amplitude. The purpose this work is assess artefacts on during isometric contractions at different lengths. average rectified value (ARV) 15 single differential was obtained means linear array 16 bar electrodes from vastus medialis and lateralis muscles. knee angle changed 75° 165° steps 30° voluntary low, medium high force level were performed for each angle. ARV pattern normalized mean activity compare joint angles. From data collected it possible separate changes due intensities activation. In three out five subjects, we found (within resolution our measures) 1 cm while no observed other two subjects. For four produces main contribution To avoid such innervation zones should be located not placed near them.